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From: worley@compass.com (Dale Worley)
Newsgroups: comp.lang.perl
Subject: need help with {n} and bracketing
Message-ID: <1991Apr5.194317.10737@uvaarpa.Virginia.EDU>
Date: 5 Apr 91 19:43:17 GMT
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Reply-To: worley@compass.com
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   From: abe@mace.cc.purdue.edu (Vic Abell)

   Can anyone help me understand why the "((\w+\s+){3})" matching and
   bracketing expression didn't create four special Perl variables?

For better or worse, because there are only two sets of parentheses
(lexically speaking), there will only be $1 and $2.  Every time the
regexp inside a pair of parentheses matches, its match is loaded into
the appropriate variable.  Thus, only the last thing to match a pair
of parentheses is available.  For example:

	(regexp)*	# $1 will be the last match of regexp

Undoing assignments to variables while backtracking is done is a bear,
but I assume that Perl does that correctly.

Dale

Dale Worley		Compass, Inc.			worley@compass.com
--
We will encourage you to develop the three great virtues of a
programmer:  laziness, impatience, and hubris.
-- Larry Wall and Randall Schwartz in "Programming Perl"